A section of Statoils Mongstad site was closed following an escape of liquefied petroleum gas (LPG), which was successfully contained and stopped, Reuters reported.
Employees were able to return to work later in the day after the situation had been dealt with, although the cause of the leak is unknown.
Oerjan Heradstveit, a spokesperson for Statoil, told the news agency that output at the refinery could be affected by the incident.
The Mongstad facility can refine approximately ten million tonnes of crude oil each year. It is the largest refinery in Norway, with all the oil processed at the plant sourced from the Norwegian continental shelf.
It exports much of its capacity to mainland Europe in the form of petrol, diesel oil, jet fuel and other light petroleum products.
Posted by Claire Manning